Vehicle safety assisting devices generally refer to devices that autonomously determine hazardous road factors for drivers, and maintain vehicles in safe and normal driving mode through mechanical and/or electronic apparatuses when approaching the hazards, or raise warning for drivers to return to safe driving mode in order to avoid accidents.
In traditional vehicle safety assisting technologies, ultra-sonar sensors are used for detecting front and/or back objects in close proximity.
Schematic diagrams illustrating operations and reflective detection of a conventional ultra-sonar warning system are shown, respectively, in FIGS. 1a and 1b. As shown, an ultra-sonar sensor 10 is disposed at the back of a car 1 for sending out an ultra-sonar signal 11a. If an object, such as another car 12 appears at the back of the car 1, the ultra-sonar signal 11a will be blocked by the car 12, and a reflected ultra-sonar signal 11b will be generated and received by the ultra-sonar sensor 10 that computes the distance between cars 1 and 12 by examining the energy of the reflected signal 11b and its arrival time. Thereafter, different types of warning signals can be sent depending on how close the object is to the car 1. For example, the closer the object is to the car 1, the louder the alarm or the brighter the warning light or the more the light bars will be.
However, a disadvantage of the conventional ultra-sonar sensor 10 is that the area that can be sensed is quite small, which limits applications to only situations like short distance or slow motion. This is because the signal strength of the ultra-sonar signal 11a decreases significantly with the increase of transmission distance. As a result, vehicle safety warning systems built on ultra-sonar sensors has limited sensing range. Furthermore, due to the limited sensing range, if the system is used in fast moving applications, the time for the drivers to react is very short, and the warning does not give enough buffer time for the drivers to respond to the imminent hazard that is about to happen.
In addition, conventional vehicle safety warning systems that are built on ultra-sonar sensors only provide an approximation of how close the driver's vehicle is to the neighboring object, there is no visual information to help the driver to assess the danger.
Therefore, there is a need for an image-based vehicle safety warning system that allows ample time for drivers to react to imminent road hazards, while further providing visual information for determining road safety.